diff --git a/phpBB/includes/functions.php b/phpBB/includes/functions.php
index 3227a21e26..30f9734efd 100644
--- a/phpBB/includes/functions.php
+++ b/phpBB/includes/functions.php
@@ -3141,172 +3141,6 @@ function phpbb_inet_pton($address)
 	return false;
 }
 
-/**
-* Wrapper for php's checkdnsrr function.
-*
-* @param string $host	Fully-Qualified Domain Name
-* @param string $type	Resource record type to lookup
-*						Supported types are: MX (default), A, AAAA, NS, TXT, CNAME
-*						Other types may work or may not work
-*
-* @return mixed		true if entry found,
-*					false if entry not found,
-*					null if this function is not supported by this environment
-*
-* Since null can also be returned, you probably want to compare the result
-* with === true or === false,
-*/
-function phpbb_checkdnsrr($host, $type = 'MX')
-{
-	// The dot indicates to search the DNS root (helps those having DNS prefixes on the same domain)
-	if (substr($host, -1) == '.')
-	{
-		$host_fqdn = $host;
-		$host = substr($host, 0, -1);
-	}
-	else
-	{
-		$host_fqdn = $host . '.';
-	}
-	// $host		has format	some.host.example.com
-	// $host_fqdn	has format	some.host.example.com.
-
-	// If we're looking for an A record we can use gethostbyname()
-	if ($type == 'A' && function_exists('gethostbyname'))
-	{
-		return (@gethostbyname($host_fqdn) == $host_fqdn) ? false : true;
-	}
-
-	if (function_exists('checkdnsrr'))
-	{
-		return checkdnsrr($host_fqdn, $type);
-	}
-
-	if (function_exists('dns_get_record'))
-	{
-		// dns_get_record() expects an integer as second parameter
-		// We have to convert the string $type to the corresponding integer constant.
-		$type_constant = 'DNS_' . $type;
-		$type_param = (defined($type_constant)) ? constant($type_constant) : DNS_ANY;
-
-		// dns_get_record() might throw E_WARNING and return false for records that do not exist
-		$resultset = @dns_get_record($host_fqdn, $type_param);
-
-		if (empty($resultset) || !is_array($resultset))
-		{
-			return false;
-		}
-		else if ($type_param == DNS_ANY)
-		{
-			// $resultset is a non-empty array
-			return true;
-		}
-
-		foreach ($resultset as $result)
-		{
-			if (
-				isset($result['host']) && $result['host'] == $host &&
-				isset($result['type']) && $result['type'] == $type
-			)
-			{
-				return true;
-			}
-		}
-
-		return false;
-	}
-
-	// If we're on Windows we can still try to call nslookup via exec() as a last resort
-	if (DIRECTORY_SEPARATOR == '\\' && function_exists('exec'))
-	{
-		@exec('nslookup -type=' . escapeshellarg($type) . ' ' . escapeshellarg($host_fqdn), $output);
-
-		// If output is empty, the nslookup failed
-		if (empty($output))
-		{
-			return NULL;
-		}
-
-		foreach ($output as $line)
-		{
-			$line = trim($line);
-
-			if (empty($line))
-			{
-				continue;
-			}
-
-			// Squash tabs and multiple whitespaces to a single whitespace.
-			$line = preg_replace('/\s+/', ' ', $line);
-
-			switch ($type)
-			{
-				case 'MX':
-					if (stripos($line, "$host MX") === 0)
-					{
-						return true;
-					}
-				break;
-
-				case 'NS':
-					if (stripos($line, "$host nameserver") === 0)
-					{
-						return true;
-					}
-				break;
-
-				case 'TXT':
-					if (stripos($line, "$host text") === 0)
-					{
-						return true;
-					}
-				break;
-
-				case 'CNAME':
-					if (stripos($line, "$host canonical name") === 0)
-					{
-						return true;
-					}
-				break;
-
-				default:
-				case 'AAAA':
-					// AAAA records returned by nslookup on Windows XP/2003 have this format.
-					// Later Windows versions use the A record format below for AAAA records.
-					if (stripos($line, "$host AAAA IPv6 address") === 0)
-					{
-						return true;
-					}
-				// No break
-
-				case 'A':
-					if (!empty($host_matches))
-					{
-						// Second line
-						if (stripos($line, "Address: ") === 0)
-						{
-							return true;
-						}
-						else
-						{
-							$host_matches = false;
-						}
-					}
-					else if (stripos($line, "Name: $host") === 0)
-					{
-						// First line
-						$host_matches = true;
-					}
-				break;
-			}
-		}
-
-		return false;
-	}
-
-	return NULL;
-}
-
 // Handler, header and footer
 
 /**
diff --git a/phpBB/includes/functions_compatibility.php b/phpBB/includes/functions_compatibility.php
index b5b60e118e..1f9131c9c0 100644
--- a/phpBB/includes/functions_compatibility.php
+++ b/phpBB/includes/functions_compatibility.php
@@ -601,3 +601,25 @@ function upload_attachment($form_name, $forum_id, $local = false, $local_storage
 
 	return $file;
 }
+
+/**
+* Wrapper for php's checkdnsrr function.
+*
+* @param string $host	Fully-Qualified Domain Name
+* @param string $type	Resource record type to lookup
+*						Supported types are: MX (default), A, AAAA, NS, TXT, CNAME
+*						Other types may work or may not work
+*
+* @return mixed		true if entry found,
+*					false if entry not found,
+*					null if this function is not supported by this environment
+*
+* Since null can also be returned, you probably want to compare the result
+* with === true or === false,
+*
+* @deprecated 3.3.0-b2 (To be removed: 4.0.0)
+*/
+function phpbb_checkdnsrr($host, $type = 'MX')
+{
+	return checkdnsrr($host, $type);
+}
diff --git a/phpBB/includes/functions_user.php b/phpBB/includes/functions_user.php
index e0b6a9d0c6..7dd850111e 100644
--- a/phpBB/includes/functions_user.php
+++ b/phpBB/includes/functions_user.php
@@ -1910,7 +1910,7 @@ function phpbb_validate_email($email, $config = null)
 	{
 		list(, $domain) = explode('@', $email);
 
-		if (phpbb_checkdnsrr($domain, 'A') === false && phpbb_checkdnsrr($domain, 'MX') === false)
+		if (checkdnsrr($domain, 'A') === false && checkdnsrr($domain, 'MX') === false)
 		{
 			return 'DOMAIN_NO_MX_RECORD';
 		}
diff --git a/phpBB/phpbb/session.php b/phpBB/phpbb/session.php
index 7624a67b05..ba200f38df 100644
--- a/phpBB/phpbb/session.php
+++ b/phpBB/phpbb/session.php
@@ -1400,7 +1400,7 @@ class session
 
 			foreach ($dnsbl_check as $dnsbl => $lookup)
 			{
-				if (phpbb_checkdnsrr($reverse_ip . '.' . $dnsbl . '.', 'A') === true)
+				if (checkdnsrr($reverse_ip . '.' . $dnsbl . '.', 'A') === true)
 				{
 					$info = array($dnsbl, $lookup . $ip);
 				}
@@ -1444,7 +1444,7 @@ class session
 		{
 			// One problem here... the return parameter for the "windows" method is different from what
 			// we expect... this may render this check useless...
-			if (phpbb_checkdnsrr($uri . '.multi.uribl.com.', 'A') === true)
+			if (checkdnsrr($uri . '.multi.uribl.com.', 'A') === true)
 			{
 				return true;
 			}
diff --git a/tests/functions/get_remote_file_test.php b/tests/functions/get_remote_file_test.php
index 75e5a6dc61..b783e3c297 100644
--- a/tests/functions/get_remote_file_test.php
+++ b/tests/functions/get_remote_file_test.php
@@ -24,7 +24,7 @@ class phpbb_functions_get_remote_file extends phpbb_test_case
 
 		$hostname = 'version.phpbb.com';
 
-		if (!phpbb_checkdnsrr($hostname, 'A'))
+		if (!checkdnsrr($hostname, 'A'))
 		{
 			$this->markTestSkipped(sprintf(
 				'Could not find a DNS record for hostname %s. ' .
diff --git a/tests/network/checkdnsrr_test.php b/tests/network/checkdnsrr_test.php
deleted file mode 100644
index 8cbd4f7e97..0000000000
--- a/tests/network/checkdnsrr_test.php
+++ /dev/null
@@ -1,67 +0,0 @@
-<?php
-/**
-*
-* This file is part of the phpBB Forum Software package.
-*
-* @copyright (c) phpBB Limited <https://www.phpbb.com>
-* @license GNU General Public License, version 2 (GPL-2.0)
-*
-* For full copyright and license information, please see
-* the docs/CREDITS.txt file.
-*
-*/
-
-/**
-* @group slow
-*/
-class phpbb_network_checkdnsrr_test extends phpbb_test_case
-{
-	public function data_provider()
-	{
-		return array(
-			// Existing MX record
-			array('phpbb.com', 'MX', true),
-
-			// Non-existing MX record
-			array('does-not-exist.phpbb.com', 'MX', false),
-
-			// Existing A record
-			array('www.phpbb.com', 'A', true),
-
-			// Non-existing A record
-			array('does-not-exist.phpbb.com', 'A', false),
-
-			// Existing AAAA record
-			array('www.six.heise.de', 'AAAA', true),
-
-			// Non-existing AAAA record
-			array('does-not-exist.phpbb.com', 'AAAA', false),
-
-			// Existing CNAME record
-			array('area51.phpbb.com', 'CNAME', true),
-
-			// Non-existing CNAME record
-			array('does-not-exist.phpbb.com', 'CNAME', false),
-
-			// Existing NS record
-			array('phpbb.com', 'NS', true),
-
-			// Non-existing NS record
-			array('does-not-exist', 'NS', false),
-
-			// Existing TXT record
-			array('phpbb.com', 'TXT', true),
-
-			// Non-existing TXT record
-			array('does-not-exist', 'TXT', false),
-		);
-	}
-
-	/**
-	* @dataProvider data_provider
-	*/
-	public function test_checkdnsrr($host, $type, $expected)
-	{
-		$this->assertEquals($expected, phpbb_checkdnsrr($host, $type));
-	}
-}
diff --git a/tests/version/version_fetch_test.php b/tests/version/version_fetch_test.php
index 188b371c47..4e8e82567a 100644
--- a/tests/version/version_fetch_test.php
+++ b/tests/version/version_fetch_test.php
@@ -42,7 +42,7 @@ class phpbb_version_helper_fetch_test extends phpbb_test_case
 		global $phpbb_root_path, $phpEx;
 		include_once($phpbb_root_path . 'includes/functions.' . $phpEx);
 
-		if (!phpbb_checkdnsrr('version.phpbb.com', 'A'))
+		if (!checkdnsrr('version.phpbb.com', 'A'))
 		{
 			$this->markTestSkipped(sprintf(
 				'Could not find a DNS record for hostname %s. ' .